Cellular phones have been popular worldwide in recent years due to its portability, multifunction, and inexpensive unit price as a communication device for social or business purpose. In an important application, an international roaming is effected by means of cellular phone. Further, as compared to conventional wire telephones cellular phones have advantages in certain fields such as convenience in an outdoor environment and portability. An additional feature of newly developed cellular phone is an embedded software called telephone book. The telephone book is comprised of a plurality of addresses stored in its memory. Each address comprises a name of a person and an associated telephone number to contact with. In use, a calling party can select a serial number corresponding to the desired name and telephone number. Once selected, the telephone number is dialed automatically.
Typically, a telephone number is set based on place where a person associated with the telephone number (i.e., resident place) prior to storing the set telephone number in the telephone book of cellular phone. For example, for Taipei residents, telephone numbers are classified either as ones belonging to the same country code or ones belonging to different country codes. Further, as to a telephone number of a country, it consists of area code and local telephone number. For example, a person may have telephone numbers such as 034780000, 0222873333, and 075872541 stored in his/her cellular phone in which 03, 02, and 07 are area codes and 4780000, 22873333, and 5872541 are local telephone numbers. Furthermore, for Taiwan residents as to telephone numbers belonging to different countries, each one consists of international code, country code, area code, and local telephone number. For example, telephone number of a friend living in Shanghai, China may be stored as 002862167654321 while telephone number of another friend living in Tokyo, Japan may be stored as 00281333933600 in which 002 is Taiwan's international code, 86 and 81 are country codes of China and Japan respectively, 21 and 3 are area codes of Shanghai and Tokyo respectively, and 67654321 and 33933600 are local telephone numbers respectively. In some countries, the international code may be replaced by a symbol of “+”. Hence, above telephone numbers of 002862167654321 and 00281333933600 may be stored as +862167654321 and +81333933600 respectively. Similarly, in use, a calling party can select a serial number corresponding to the desired name and telephone number. Once selected, the telephone number is dialed automatically.
Above dialing procedure is only applicable to calls made within the resident place. In other words, it is not applicable to calls made while roaming. In fact, a calling party has to make some adjustments to a desired telephone number based on difference between the same telephone number dialed in resident place and roaming place. For example, a calling party desires to dial a telephone number associated with resident place from a roaming place, numeral “0” in the area code has to be replaced by country code of resident place and international code of roaming place sequentially in the telephone number because dialing of the telephone number associated with resident place is not applicable to dial an international call at the same country. Typically, area code of domestic call has a numeral “0” in the beginning while the numeral “0” has to be removed while making an international call. For example, in a case that the roaming place is China above telephone numbers such as 034780000, 0222873333, and 075872541 belonging to friends in Taiwan (i.e., resident place) are required to modify as 0088634780000, 00886222873333, and 0088675872541 prior to making a successful dialing. As to making a call to a friend living in Tokyo, Japan, the international code of the called party's telephone number (e.g., 002) has to be replaced by numerals “00” in advance. In other words, telephone number of 00281333933600 has to be changed as 0081333933600 prior to making a call. As to making a call to a friend living in Shanghai, China, the international code and the country code of the called party's telephone number (e.g., 00286) has to be replaced by numerals “0” in advance. That is, telephone number of 002862167654321 has to be changed as 02167654321 prior to making a call. Only above adjustments have been made, a calling party can make a call successfully to a telephone number by selecting a corresponding serial number from telephone book while roaming.
However, the prior art suffered from several disadvantages. For example, a cellular phone user can not easily identify the adjusted telephone number. Moreover, another adjustment procedure has to be performed with respect to above adjusted telephone numbers after the cellular phone user has returned to his/her resident place. This is a tedious and time consuming process. To the worse, it can be very bothersome and bring much inconvenience to a cellular phone user who frequently travels to different countries.
Thus, it is desirable to provide a novel method for automatically converting a stored telephone number of cellular phone into one to be adapted for dialing in a different country in order to overcome the above drawbacks of prior art.